'electronic ruler' is a concept that has been designed by shay shafranek and oded webman
with the support of udk industrial design department, berlin.

so how does it work? by pressing the button the digits illuminate and the ruler is ready to go. passing a pencil along the edge of the ruler will make the numbers go up or down according to the length of the line. pressing the button again will reset the value.






touching the ruler after resetting defines a new zero point. now touching other points
along the ruler will give the definitive distances to the zero.

via designboom